The 7/7 rescue operation was hampered by problems that were identified but not tackled after the King's Cross fire 18 years earlier, an inquest heard today.

Some of the recommendations in Sir Desmond Fennell's report into the 1987 tragedy have still not been implemented nearly six years after the 2005 terrorist attacks, the hearing was told.

In particular, the radio system used by London Underground staff remains not fully compatible with that used by the emergency services.

Sir Desmond's report into the November 18 1987 fire at King's Cross Underground station, which killed 31 people, highlighted serious concerns about communications on the Tube.

The inquest into the July 7 2005 attacks on London has heard that radio problems meant rescuers battling to save lives on bombed Underground trains could not pass information and requests for more help back to the surface.

Hugo Keith QC, counsel to the inquest, noted: "Some of the things that went wrong on 7/7 were direct reflections of issues identified by Fennell which had not been corrected or addressed fully by the time of July 7."

Geoff Dunmore, London Underground's operational security manager, admitted that relaying information from the Tube trains made the emergency response to the attacks more difficult.

"The root causes of a lot of the problems was the fact that we couldn't get communication directly from the trains to the outside world, including our own controls," he said.

He said the introduction of a new radio system for London Underground staff, known as Connect, since the 2005 bombings, had addressed this issue.

"Of course with these type of incidents you can never guarantee that a communications system will stand up totally but it is a lot more resilient than anything we've had previously," he said.

Mr Dunmore also insisted that London Underground learned lessons from the King's Cross fire before the July 7 attacks.

He said: "If you consider for a moment the overall response to July 7, a lot of what we had in place in terms of emergency planning and training and things like rendezvous points is a direct outcome of Fennell."

Sir Desmond's report said it was "essential" for communications between London Underground and the emergency services to be inter-operable, Mr Keith said.

Mr Dunmore admitted it would be technically possible to make Tube workers' Connect radios compatible with the emergency services' Airwave system.

But he said: "It's also whether it would give you any real benefits of having that.

"Because quite simply if you needed someone from the emergency services - an example, as we've had with July 7, to talk to a member of our staff down a tunnel - we could simply give them a Connect radio at the station for them to do that."

Howard Collins, Transport for London's chief operating officer, added: "There are protocols to ensure that the loaning of handsets can happen.

"Often those handsets look and function in the same way, but I think the issue for us is that the police and emergency services' network is a secure, encrypted system and certainly our system uses the commercially available bands."

A further Fennell report recommendation that the radios used by British Transport Police and London Fire Brigade should be compatible in Underground stations was also not in place by July 2005, the inquest heard.

Asked about this, British Transport Police Chief Inspector Brian Gosden said: "I can't comment on the history of that as to why it wasn't implemented."

The inquest has heard that some firefighters refused to go into the Tube tunnels to help 7/7 survivors until London Underground had formally confirmed the power had been turned off.

Mr Dunmore was critical of London Fire Brigade guidelines advising firefighters to call their own control room to check it was safe to go on to the tracks.

"So they're relying on somebody that's far removed to give them confirmation through a third or fourth party that traction current is off," he said.

"The daft thing about all that is that we will always refer them back to the local supervisor to give them confirmation that current is off. We never do it through the control room.

"What we are doing, separately to this, is talking to the fire brigade, and then with the other emergency services, about coming up with a system that is done locally that gives them the safe system that they require to work with their people as well."

The coroner, Lady Justice Hallett, asked him: "That sounds as if it's present tense, and I wondered why nearly six years after the event when you knew they had problems getting confirmation, there are still these discussions.

"Is that because it's continual discussions improving things, or is that discussions to get in place a proper system?"

Mr Dunmore replied: "I think it's the continual discussion to improve things. To be perfectly fair until this inquest that didn't feature as an issue particularly around the incidents on July 7."

The new Airwave system allows police officers to use their radios on the Tube network, the inquest heard.

London Fire Brigade uses Airwave above ground but employs an old analogue system underground.

Chief Inspector Philip Short, of British Transport Police, agreed that the emergency responders who braved smoke-filled Tube tunnels to rescue 7/7 survivors would have been greatly helped if the new radios had been available in 2005.

He said: "That's undoubtable. If Airwave was working on the Underground at that time, the response would have been far enhanced."

The bombings carried out by Mohammed Sidique Khan, 30, Shehzad Tanweer, 22, Hasib Hussain, 18, and Jermaine Lindsay, 19, were the worst single terrorist atrocity on British soil.

The inquest at the Royal Courts of Justice in London, which is due to finish in March, was adjourned until tomorrow.